object FunDemo01 {
  def main(array: Array[String]): Unit = {
    val n1 = 10
    val n2 = 20
    val oper = '-'
    val unit = getRes(n1, n2, oper)
    println(unit)
  }

  def getRes(n1: Int, n2: Int, oper: Char) = {
    if (oper == '+') {
    } else if (oper == '+') {
      println("res=" + (n1 - n2))
    }
    null
  }
}
